Friday Night

Severe Weather Alert Descriptions

Special Statement Statement as of 3:21 am EDT on March 31, 2015

... Increased fire danger this afternoon...

The combination of low relative humidities and gusty southwestwinds will produce an increased fire danger threat this afternoon.Winds are expected to gust up to 30 mph with humidity levelsdropping to between 20 to 30 percent.

Residents are urged to exercise caution handling any potentialignition source... including machinery... cigarettes... and matches.Be sure to properly discard all smoking materials. Any dry grassesand tree litter that ignite will have the potential to spreadquickly.

Virgina residents are reminded that open burning is prohibited before4 PM each day through April 30th.

NWS Forecaster Discussion

Area forecast discussion
National Weather Service Wakefield Virginia
417 PM EDT Tuesday Mar 31 2015
Synopsis...
low pressure will track across the northern middle Atlantic region
early this evening...before pushing offshore late in the evening
and overnight. High pressure will build over the area on Wednesday...and
gradually shift off the coast on Thursday. The next cold front approaches
from the northwest on Friday...and crosses the region Friday night
into Saturday morning.
&&
Near term /until 6 am Wednesday morning/...
afternoon surface analysis reveals low pressure centered over northern Virginia/western
Maryland/south central PA. Breezy warm day across the local area with
temperatures mainly from 70-75 f over interior Virginia/NE NC...with 60s
prevailing on the Eastern Shore and the immediate coast of Virginia/NE NC.
Skies are still sunny/mostly sunny for the most part...but latest
satellite reveals broken/overcast cloud cover in the vicinity of the surface
low and given a west-northwest flow aloft...expect skies to become partly to
mostly cloudy for northern portions of the akq County Warning Area over the next
few hours. Dew points remain very low (mainly in the 20s to lower 30s)...so
precipitation chances will generally be confined to far northern/NE sections
of the County Warning Area...primarily from 22z through 02z this evening (although
will have some low chance probability of precipitation prior to this over the far north).
Some of the high- res model data still depicts measurable quantitative precipitation forecast all
the way into southern Virginia/NE NC. Given how dry it will be and that
current observation upstream are showing rain having a tough time
reaching the ground S/SW of the surface low track...will favor a drier
forecast close to that depicted by the 12z nam12. Will confine low
end likely probability of precipitation to the Maryland zones...with just chance/slight chance for
remaining zones mainly along/N/NE of I-64. Generally going with a dry
forecast S/SW of I-64.
Wind speeds will average 15-20 miles per hour with gusts mainly up to 25-35
miles per hour into the early evening hours. The combination of dry and breezy
conditions will enhance fire danger through sunset so the fire weather statement
has been issued. See fire weather section below for more detailed information.
Conds dry out quickly after midnight with skies becoming mostly
clear with low temperatures mainly in the upper 30s to middle 40s.
&&
Short term /6 am Wednesday morning through Friday/...
Canadian high pressure returns to the region on Wednesday. A cooler day
under mostly sunny skies should be anticipated with highs in the
Lower-Middle 60s for interior southern Virginia/NE NC and in the middle- upper 50s
closer to the coast as winds turn onshore in the afternoon as the
pressure gradient weakens. Surface high pressure axis shifts offshore
late Wednesday night. Light winds and mostly clear skies should result
in overnight lows in the middle 30s to around 40 most locations.
With surface high pressure axis offshore on Thursday and a weather
disturbance approaching the region from the SW...the area will be
within a warming airmass especially as breezy south winds develop
by the afternoon. Most inland locations should reach the lower 70s once
again under mostly sunny skies...with highs in the middle- upper 60s
at the immediate coast. Increasing clouds Thursday night as upper ridge
axis shifts off the coast and a more moist SW flow aloft develops.
In general...models are slower at bringing in deep moisture and
the northern stream and southern stream are slower to phase. Have scaled
back a bit on probability of precipitation for Friday...looks like a low end chance for mainly
-ra Friday morning...primarily across northern zones as low level moisture
overspreads the region. Very mild Thursday night in south-southwest flow and
incraesing clouds...lows in the 50s to possible as warm as 60 f in
a few spots. Warm/variably cloudy Friday with 20-30% chance for -shra
and perhaps some late day thunderstorms as the surface front moves closer to
the region. Highs mainly in the middle-upper 70s...possibly close to
80f if enough sun can prevail. Main rain event looks to hold off
until Friday night described in the long term below...
&&
Long term /Friday night through Tuesday/...
extended period will start off wet as a cold front crosses the
region Friday night-Sat morning. Still some minor spatial and timing
differences in the models with respect to associated southern stream energy and the
cold front...but mostly now with how quick precipitation clears the coast
Sat. Have increased probability of precipitation to likely Friday night...except the southeast. Theta-
east advection and mild temperatures will result in marginal instability Friday
evening. Soundings also indicate sharpening lapse rates as temperatures
aloft cool. Will introduce slight chance thunder Friday evening. Cold
front exits the coast Sat as the parent low and shortwave energy
lift into the NE states/Canadian Maritimes. High pressure builds in
from the west late Sat...remaining over the region through sun. The
result will be dry conditions with a mostly sunny sky and slightly
below normal temperatures. Highs Sat-sun generally in the low 60s inland
and middle-upper 50s Eastern Shore and coastal areas. Lows Sat night in the
upper 30s to low 40s. Broad upper trough will remain over southeastern
Canada through the weekend into early next week. Associated backdoor
front will remain north of the region. High pressure pushes offshore
sun as return flow begins to moderate temperatures. Moisture from
the Gulf begins to spread back northward into the Midwest early next week
as weak perturbations in the westerly flow cross the region. Begin to
reintroduce slight chance-low end chance probability of precipitation Tuesday-Tuesday night. Highs
Monday in the middle-upper 60s inland and upper 50s to low 60s Eastern Shore
and coastal areas. Lows Monday night in the upper 40s-low 50s. Highs
Tuesday in the low 70s inland and middle-upper 60s Eastern Shore and coastal
area.
&&
Aviation /20z Tuesday through Sunday/...
VFR conditions are expected to persist through the 18z taf
period. A cold front moves through the area this evening. Ahead of
this front...gusty SW winds (25-30 kt) are expected until around
22-23z.
A brief -shra cannot be ruled out at ksby this evening. Dry weather and
VFR conditions then expected Wednesday and Thursday. Gusty SW winds may again
be possible Thursday afternoon.
&&
Marine...
low pressure has located over northern Virginia this afternoon with a trailing
cold front located along the Ohio Valley. Strong gradient over the
region between low pressure and high pressure off the Florida coast has
resulted in strong SW winds over the water this afternoon. Speeds
generally 15-25 knots. Few gusts of 30 knots observed on elevated sites
closet to land...where 30 knots gusts also observed. Seas generally 2-3
feet and waves 1-3 feet. Seas build to 3-5 feet northern waters this evening.
Low pressure pushes offshore this evening with the cold front
sweeping across the water around midnight. Brief lull in Small Craft Advisory speeds
expected this evening in advance of the front...but a northwest cold air advection surge
expected Post frontal. Speeds increase to 20-25 knots with a few gusts
up to 30 knots after midnight. Seas build to 4-5 feet all coastal zones
with waves 3-4 feet. Small Craft Advisory conditions will be relatively short lived as
high pressure quickly builds over the waters Wednesday morning. Southeast swell
may keep seas hovering around 5 feet 20 nm out through Wednesday morning...but
subsiding Wednesday afternoon. High pressure slides offshore Wednesday night
with flow returning to the S at or below 15 knots. Southerly winds increase Thursday as
a cold front approaches from the west. Marginal Small Craft Advisory conditions are
possible late Thursday-Thursday evening with southerly winds around 15-20 knots.
Seas in the northern waters also prognosticated to reach 5 feet. Flow becomes SW
Friday as the front hangs up along the central Appalachians. Front
finally crosses the waters late Friday night. Brief period of Small Craft Advisory
conditions expected Sat morning before high pressure builds in
from the west. High pressure remains over the water through the
weekend.
&&
Fire weather...
southwest winds 15-20 miles per hour with frequent gusts between 25-35 miles per hour
are expected this afternoon/early evening. These winds in
combination with relative humidity values dropping to 18 to 25%
range across Virginia and northeast NC will increase the fire danger.
After coordinating with the NC and Virginia forestry officials and
surrounding National Weather Service offices...will maintain an enhanced Fire Danger
Statement through 6 PM. Critical red flag criteria may be met in a
few locations across the Virginia Piedmont. However...10-hr dead fuel
moisture values are still marginal or slightly exceeding the
necessary threshold of 7%. On the Eastern Shore...a statement will
not be necessary due to higher minimum relative humidity values.
&&
Akq watches/warnings/advisories...
Maryland...none.
NC...none.
Virginia...none.
Marine...Small Craft Advisory until 10 am EDT Wednesday for anz630>638.
Small Craft Advisory until noon EDT Wednesday for anz650-652-
654.
Small Craft Advisory from 4 am to noon EDT Wednesday for
anz656-658.
&&
$$
Synopsis...lkb
near term...lkb
short term...lkb/mas
long term...Sam
aviation...jdm
marine...alb/Sam
fire weather...